The day after Islamic militants swept into Mosul, Iraq's second-largest city, and several other enclaves along the Tigris River, the conquering army, called the Islamic State of Iraq and al-Sham, posted a photograph on Twitter. It showed one of its fighters—a Chechen volunteer, the group said—opening the door of an American-made Humvee that it had seized from the Iraqi Army. The Humvee and the militant, the group said, had just arrived at an ISIS base in Syria, where, presumably, they were ready to be dispatched in the war there.

The border between Iraq and Syria may have effectively disappeared, but the dynamics driving the civil wars in those nations are not identical. In Syria, an oppressed majority is rising up; in Iraq, an oppressed minority. (The opposition fighters in both wars are mostly members of the Sunni sect.) Both countries just held elections: in Syria, the dictator, Bashar al-Assad, won in a display of empty theatre; in Iraq, where Prime Minister Nuri al-Maliki is expected to form a government for a third term, the elections were for the most part free. In Iraq, the dynamics driving the strife are largely Iraqi, and in Syria they are largely Syrian.

Even so, the events unfolding in Iraq point toward a much wider war, reaching from the Iranian frontier to the Mediterranean coast. The long open border between Iraq and Syria, and the big stretches of ungoverned space, has allowed extremists on each side to grow and to support one another. ISIS and Jabhat al-Nusra, two of the strongest groups fighting in Syria, were created by militant leaders from Iraq, many of whom had fought with Al Qaeda in Mesopotamia against the United States. The vast swath of territory between the Euphrates and the Tigris—from Aleppo, in Syria, to Mosul, in Iraq—threatens to become a sanctuary for the most virulent Islamist pathologies, not unlike what flourished in Afghanistan in the years before 9/11. Among those fighting with ISIS and Al Nusra are hundreds of Westerners, from Germany, the United Kingdom, France, and the United States. At some point, the survivors will want to go home; they will be well trained and battle-hardened.

The extremist groups dominating the fighting are beginning to take their war beyond the two countries that they now freely traverse. In January, ISIS carried out a car-bomb attack in Beirut near the offices of Hezbollah, the Lebanese militant group that has been fighting on behalf of Assad. The Nusra front has also carried out attacks in Lebanon. Meanwhile, the number of Syrian refugees who have fled to that nation exceeds twenty per cent of its population, which is not something that a state as weak and as fractious as Lebanon can be expected to sustain. In Jordan, the presence of half a million Syrian refugees is putting an enormous strain on the fragile monarchy.

The revolutionary government of Iran looms ominously over it all. Iran has been decisive in supporting Assad, and its influence over Maliki, never small, has increased enormously since the departure of the last American forces in Iraq, in December of 2011. During the war, Iranian agents trained, armed, and directed a network of Shiite militias, which killed hundreds of American and British soldiers. Those same militias are evidently being readied to confront the Sunni onslaught in Iraq; thousands of their members have already been fighting for Assad in Syria. Iran's intervention in Syria has also alarmed Saudi Arabia and Turkey, which have poured in guns and money to help the rebels. It is not difficult to imagine a multinational war, fought along a five-hundred-mile front, and along sectarian lines, waged ultimately for regional supremacy.

What can the United States do? It has already done quite a bit, of course. The invasion of Iraq, in 2003, by destroying the Iraqi state, empowered the Shiite majority—Maliki in particular. As long as American troops remained in Iraq, they could restrain Maliki and his Shiite brethren from their worst sectarian impulses. By the time the last troops departed, the civil war, which began in 2006, had been brought under control. But, in the two and a half years since the troops' departure, Maliki has been free to pursue a stridently sectarian project, which has cut the Sunnis off from political power. He has alienated—even, in some cases, arrested—the most reasonable Sunni leaders and embarked on mass arrests of young Sunni men. In the process, Maliki has to a great extent driven the Sunnis back into the arms of the extremists. Indeed, in the sectarian calculus that now dominates Iraqi politics, Sunni unrest has worked largely in his favor, as it has allowed him to portray himself as the Shiites' protector. The Iraqi state, built mainly by the Americans, is too feeble to resist the Sunnis' efforts to break away.

For a time, in the waning months of the occupation, the White House and Maliki considered keeping some American troops in Iraq, in non-combat roles, ostensibly to train soldiers but also to help manage the nation's politics. No deal was ever struck, and it's difficult to imagine any appetite in Washington today for a substantial American reëntry into Iraq. But, with the militants nearing Baghdad, and the Iraqi Army faltering, President Obama will almost certainly feel compelled to act. Already, the U.S. has been rushing sophisticated weaponry to the Iraqi Army. The question now before the President is whether to take more significant steps, such as air strikes.

In Iraq, as in Syria, the choices are almost all bad, and the potential for American influence is limited. Syria appears to be headed toward an effective partition between predominantly Sunni and predominantly Alawite enclaves, and an impoverished, Somalia-like future where guns rule. In Iraq, the Kurds, the third big group, are taking advantage of the chaos by tightening their hold on Kirkuk and other disputed areas, in an effort to cement a future separate from that of the rest of Iraq. At the least, Iraq faces a future as a violent country, with a weak central government and many areas dominated by extremists. But things could get much worse than that.

Within a day after sweeping into Mosul, ISIS militants freed thousands of prisoners, looted bank vaults, and declared the imposition of Sharia law. From now on, the group said, unaccompanied women were to stay indoors, and thieves would be punished by amputation. The "divine conquest" of Mosul by a group of Islamic extremists is a bitter consequence of the American invasion. For now, there seems to be very little we can do about it.

KOTA KINABALU: A police lance corporal is believed to have shot his would-be wife's uncle before taking his own life in Sabah's east coast Sandakan town.

The 28-year-old L/Kpl Salleh Maudidi, who is with the General Operations Force in Sandakan, was found with a single gunshot wound to his head.

The body of his wife's uncle, watchman Ibni Hashim, 66, with three bullet wounds was found several metres away from L/Kpl Salleh's body at the entrance to the construction site at North Road at 11.30am yesterday.